ESP32-C3 CO2 Monitor

A Rust-based air quality monitoring system using ESP32-C3 microcontroller, SCD41 CO2 sensor, and SSD1306 OLED display.

Features

• Measures CO2, temperature, and humidity using Sensirion SCD41 sensor
• Displays readings on a SSD1306 OLED display
• Broadcasts readings over BLE (GATT server)
• Written in Rust using esp-idf framework
• Periodic measurements with configurable interval
• Error handling and display
• Automatic disabling of the onboard LED (GPIO 8) to prevent interference

Hardware Requirements

• ESP32-C3 development board (e.g., ESP32-C3 DevKitM-1)
• Sensirion SCD41 CO2 sensor
• SSD1306 OLED display (128x64)
• I2C connections:
  • SDA: GPIO4
  • SCL: GPIO5

Building and Flashing

1. Install Rust and ESP-IDF toolchain
2. Clone the repository:

   git clone https://github.com/arietis/esp32-co2-monitor.git
   cd esp32-co2-monitor

3. Build the project:

   cargo build

4. Flash to ESP32:

   cargo run

Configuration

The default measurement interval is 5 seconds. You can modify this in src/main.rs:

const MEASUREMENT_INTERVAL_MS: u32 = 5000;

BLE

The firmware exposes sensor readings over BLE using a custom GATT service:

• Device name: ESP32-CO2
• Service UUID: c892f08b-0502-49a6-8c52-b959aa997e54
• Characteristics:
  • CO2: 00002b8c-0000-1000-8000-00805f9b34fb
  • Temperature: 00002a6e-0000-1000-8000-00805f9b34fb
  • Humidity: 00002a6f-0000-1000-8000-00805f9b34fb

License

This project is licensed under the MIT License - see the LICENSE file for details.